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Router feed direction and bit rotation

Keith Larrett — Wed, 04 Nov 2009 23:18:44 +0000

I recently purchased a set of Rockler’s Bench Cookies. I’ve been reading about them all over the internet and no doubt I’m probably the last woodworker in the world to have purchased a set I was excited to try them out and thought I would combine it with an article about router feed direction and bit rotation.

I use a router a lot in my workshop, both hand held and table router. However, I can remember when I got my first router and the learning curve I went through figuring out which direction to move the router when routing by hand or the workpiece when routing on the table router. Hopefully I can help others out and make that learning curve not quite as exciting!

Essentially the workpiece always needs to be feed into the bit, so the first thing you need to know is which way is the bit rotating. Lets deal with the table mounter router first. Hold out your right hand in a classic “thumbs up” gesture. Imagine your hand is the router and your right thumb is the router bit. The direction of the router bit follows the curve of your fingers. In this case, it is counter clockwise. You can see this clearly in the picture below.

Now rotate your right hand into a “thumbs down” gesture. Again imagine your hand is the router and your right thumb is the router bit. The direction of the router bit is still indicated by the curve of your fingers, in this case it is clockwise. You can see this in the picture below.

This “right-hand thumb rule” applies to almost anything that spins, faucets, right hand thread screws etc.

So, moving back to the router table, you can see that in order to feed the workpiece into the router bit, you need to feed from right to left, assuming you are standing facing the fence. By feeding from right to left you are feeding the workpiece against the direction of rotation of the bit. The natural reaction as the workpiece contacts with the bit is to push the workpiece back towards you. By controlling the workpiece, by hand and through the use of featherboards, you prevent this from happening.

Feeding from left to right, the rotation of the bit would grab the workpiece and pull it forcefully from right to left. This can happen in the blink of an eye and the danger is, aside from ruining the workpiece, that you don’t release it and your fingers are pulled towards the router bit.

For the same reason the fence always needs to be positioned so that side of the router bit that is furthest away from the fence is doing the cutting. To illustrate, suppose you need to route a groove or dado that is 1″ wide, but the largest bit you have is a 3/4″ straight bit. Obviously the groove will have to be cut with two passes. The first pass will form a 3/4″ groove and then the fence can be moved 1/4″ in order to make the groove a full 1″ wide after the second pass. No problem.

However, it is very important that the fence be moved in the right direction before the second pass. Moving the fence closer to the router bit would mean that the side of the router bit that is closest to the fence is doing the cutting. Remember the way the bit is rotating? This would cause the bit to pull the workpiece away from you forcefully. The following picture shows what not to do!!

The correct method is to move the fence away from the router bit so that the 1/4″ section of the groove you are removing with the second pass is on the side of the router bit farthest from the fence. The following picture show the correct position of the fence relative to the router bit. By setting up for the second pass this way you are once again feeding the workpiece into the direction of rotation of the bit.

Cuts like this need to be planned very carefully to ensure that the correct side of the router bit is doing the cutting.

Moving back to the hand held router, there are two different scenarios which determine feed direction. Imagine a circular picture frame that you need to profile both the external and internal edges of. Which direction to you rout?

Hold your right hand out again with fingers closed except your thumb and index finger. Imagine your hand is the router. If your right thumb is pointing to the workpiece then your index finger is showing the direction of travel of the router. Take a look at the picture below.

You can see that when routing the outside edge of the picture frame, you need to move the router in a counter clockwise direction. When routing the inside edge of the picture frame, you need to move the router in a clockwise direction.

I have found these two “right hand” memory aids very useful in determining router bit rotation and router feed direction. I hope you do to.

I’ll end the article with a short video clip showing the Rockler Bench Cookies supporting a workpiece I was making some test cuts on. I found they held the workpiece securely and it was nice to have it raised above the table. I did find that I needed to lightly support the workpiece with my inboard hand to prevent it from tipping slightly. I’m sure that if the workpiece was wider or if I had been using an offset base on the router, this would not have been necessary. I can also see the Bench Cookies will be useful for other applications, sanding and finishing are two that come to mind.

In full disclosure, the links are affiliate links. If you purchase anything from Rockler via the links, Rockler will send me buckets of money and I’ll be able to quit my day job and play in my workshop every day. Not necessarily a bad thing

Inlaid half blind dovetail joints

Keith Larrett — Sun, 04 Oct 2009 17:45:29 +0000

I planned to make inlaid half blind dovetail joints for the frame of the knife display case. The frame is made from African Mahogany and the inlays are tiger maple. This article will show how I made the joints. For more information on the Leigh Jig please visit their website. The article which I followed is one of Leigh’s technical bulletins. Their manuals are very well written and illustrated. Another excellent source for information on the Leigh Jigs is Al Navas’s blog, Sandal Woods.

When making half blind dovetails with the Leigh Jig it is critical to understand the following:

Bit selection is based on the thickness of the pin board.
The bit selected will only produce one specific cutting depth. If you have the bit set to low the joint will be too tight, if you have the bit set to high the joint will be too loose. Only one depth of cut will make a perfect joint.
The pins and the tails are both routed with the same bit.
The scale setting determines how much the pins protrude from the tails. You only want the pins to protrude by about 1/64″ to make for easy clean up of the joint.

The process for making inlaid half blind dovetail joints consists of first making a set of end on end half blind dovetails with two pieces of contrasting woods. Then making a regular half blind dovetail joint where the tails are smaller.

The first step was to prepare the lumber to the right dimensions. While I was doing this I also prepared a couple of test pieces to use in setting up the router and jig and to practice the joint on. I marked all the pieces with white chalk, indicating the sides of the frames (the tail boards) and the front/back of the frame (the pin boards). I also marked the show side or outside of the frame.

As well as the four sides of the frame, I also needed to prepare a spacer board, the inlay board and two shims. The spacer board is used on the Leigh Jig to rest the guide fingers on. The shims are used to help set the fingers of the jig when doing the inlay. The inlay board and shims needed to be milled to a particular thickness. The pin and tail boards are 5/8″ thick and I wanted an inlay of 1/16″ thickness. I was using the 120-8 cutter (router bit) which has a 14 degree angle and a cutting depth of 7/16″.

The inlay board thickness needed to be equal to the cutting depth + inlay thickness. i.e 7/16″ + 1/16″ = 1/2″

The shim thickness was determined by the following formula in the Leigh Bulletin: inlay thickness x 1.28 i.e 1/16″ x 1.28 = 0.08″ (The angle of the cutter bit determines the factor by which you multiply the inlay thickness by in order to determine the shim thickness.

Having prepared all the lumber the next step was to layout the fingers on the jig. As my board was only 2 1/2″ wide there were not going to be many dovetails! It is important to make sure that you have room for at least two shim thickness between each pair of fingers. The guide fingers need to be moved by this amount later in the proceedings.

The assembly is then rotated into the half blind pins mode with the scale set to the thickness of the tail board. The pin board is placed horizontally in the jig and moved forward so that it touches the tail board that is vertical in the jig. You can see in the image below that the tail board is set low enough that the router bit will not touch it!

The pin board is then routed. This is not the normal procedure when making half blind dovetails using the Leigh Jig. Normally the tail board is routed first. For inlaid half blind dovetails the pin board needs to be routed first so that an inlay can be glued into the pins.

The assembly is now rotated to the half blind tails mode and the inlay board is placed horizontally in the jig. It is moved forward so that it is flush with the front face of the tail board mounted vertically in the jig. The inlay board is routed out. When routing the inlay board you need to make sure you route back far enough so that there is enough of a tail to fill the tail sockets.

After making a test fit I took the inlay board to my cross cut sled on my table saw and cut off a couple inches of the end which had been routed. I then glued the inlay into the pin board. As you can see in the image below I did this on both ends of the pin board.

Once the glue had cured, I took the piece to my cross cut sled again and cut the inlay board flush with the end of the pin board.

Now comes the magic trick. With the jig assembly still in the half blind tails mode the guide fingers need to be moved so that the next set of pins and tails that are cut are slightly smaller than the first set. The Leigh Bulletin does a great job of explaining how the guide fingers need to be moved, I’ll do my best here.

The right hand fingers are loosened and moved to the right by one shim thickness. They are then tightened. The left hand fingers are then loosened, slid to the left so that two shims fit between the left and right fingers, then the left finger is tightened. The half pin guides need only to be moved inwards by one shim thickness. The easy way to do this is to move the “spare” fingers (the ones to the far left and right of the joint that are just used to rest the router on) flush to the half pin guides. Then the half pin guides are loosened, slid in by the the thickness of one shim and tightened. The “spare” guides are then moved back out. It sounds pretty complicated, but it is actually fairly simple to do.

Having moved the guides, and with the assembly still in the half blind tails mode, the tail board is routed out. As you can see in the image below the tail board is mounted vertical in the jig and raised so that it touches the underside of the guide fingers.

We’re nearly there!! The assembly is rotated to the half blind pins mode. The pin board with the inlay is mounted horizontally in the jig and moved forward so that it touches the tail board that is vertical in the jig. Again you can see in the image below that the tail board is set low enough that the router bit will not touch it!

The pin board is routed out and finally the inlaid joint is revealed! I don’t need to tell you how exciting a moment this is!

The results of all those steps, an inlaid half blind dovetail joint.

Pockets for the knives

Keith Larrett — Mon, 28 Sep 2009 15:35:45 +0000

After completing a test piece, it was time to route out all the pockets for the knives. 19 knives in total, with the pockets to be routed in a beautiful piece of 7/8″ thick tiger maple. A little nerve wracking to say the least!

Here are some progress pictures. The Eagle head of the pocket was routed first as that was the deepest pocket.

Next the main body of the knives were routed out.

I then removed the 1/4 plywood template from the back of the maple. That in itself was a struggle, it’s amazing how strong double sided carpet tape is! Using a 1″ forstener bit I drilled semi circles above the template of each knife. This was to be the guide to route out a small finger pocket. I then clamped the plywood to the front of the maple and using a plunge router with a core bit and collar cut out the finger pockets.

Here is a detail shot of one of the knife pockets.

Finally here is a shot of the tiger maple board complete with all the knives. I was pleasantly surprised when each knife dropped neatly in it’s designated pocket

The next step will be to make the frame of the case. I plan on using African Mahogany with half blind dovetail joints inlaid with maple.

Pockets for knife display case – test piece

Keith Larrett — Sun, 20 Sep 2009 20:05:24 +0000

I decided to do a test piece for the pockets I will be making for the knife display case. I’ve learned the value of test pieces from bitter experience. The extra time taken always seems to pay dividends as you figure out a process using a piece of scrap wood.

The first step was to trace the pattern of a knife onto a piece of 1/4″ plywood and onto a piece of scrap maple. I also drew a line on the pattern separating the thicker eagle head portion of the knife from the rest of the handle.

Using my scroll saw I cut out the eagle head portion of the pattern in the plywood. On the maple piece I hogged out the same portion using a 3/4″ forstner bit in my drill press. I set the drill press so that it would drill to a depth just slightly less of the final depth of the pocket.

Then, taking care to orientate it correctly, I attached the plywood to the back of the maple with double stick tape, and using a 3/4″ router bit and the Daisy Pin Router, I routed out as much of the pocket as I could.

Because of the diameter of the 3/4″ router bit I was not able to route out the area of the pocket at the eagle’s beak. So I switched to a 1/8″ router bit and also changed the guide pin in the Daisy Pin Router to 1/8″. With the smaller diameter bit I was able to access and rout out the area at the eagle’s beak.

I then removed the plywood from the maple test piece, and took it back to the scroll saw, where I cut out the rest of the pattern. I also took the maple piece back to the drill press and hogged out as much as I could with the forstner bit. You can see that portion of the pocket will not be as deep as the eagle head portion.

The 1/4″ plywood was taped to the back of the maple piece again, and I switched both the router bit and Daisy Pin Router guide pin back to 3/4″. Then the pocket was routed out. Because this section of the pocket was not as deep I did not have to do a plunge cut with the router. I simple placed the piece over the router bit in the deeper pocket, turned the router on and then moved the piece across to route out the shallower section.

The completed pocket with the knife sitting in it.

With a total of 19 pockets to create in the actual knife display case, it was worth taking the time to make a test piece and find the most efficient and accurate method.

Daisy Pin Router

Keith Larrett — Sat, 19 Sep 2009 19:55:42 +0000

My initial plan to create the slots holding the knives in the display case was to use my scroll saw. However, the case dimensions were 16″ x 30″ which would have been to big for my scroll saw. Further, when I took delivery of the knives I saw the eagle part of the handle was considerably thicker than the rest of the handle. This meant the slots would have to be at a varied depth in order for the knives to sit flat. The only way to achieve this would be with a router.

Rather than having to factor in the thickness of a router collar when making the template, I decided to buy a Daisy Pin Router from MLCS Woodworking. Like I really needed an excuse to buy a new tool The pin router includes four steel guide pin of varying sizes (1/4″, 5/16″, 3/8″ and 1/2″) and I also purchased the corresponding set of router bits to go with the pin router. As always, with MLCS, shipping was prompt and the package arrived in good condition. As you can see in the next shot, some assembly and set up is required.

After attaching the lever to the arm, I screwed the 1/2″ guide pin into the collet of my router. I then moved the arm around to see where it would fit best. Ideally I would have preferred bolting it to the table on the fence side of the router. However, I had very limited access to the underside of my router table at that location, so it would have been difficult tightening and removing the bolts. I ended up locating it to the left and back of the router. This meant that I would need to feed the workpiece from right to left, which shouldn’t be a problem as I have enough of the table in front of the router to support the workpiece. I also took care to make sure the arm did not cover the access hole for the router lift.

The next step was to mark where the four holes were to be drilled in the router table. I used a transfer punch to do this accurately. I drilled the holes carefully using a 5/16″ bit. The directions called for using a 3/8″ bit, but that seemed a bit big to me.

The next shot shows the pin router bolted to the table with the 1/2″ pin still secured in the router collet.

I was excited to take it for a test drive, so I cut a scrap piece of 1/4″ plywood, drilled a hole in it with a forstner bit and then secured it to a piece of maple with double sided tape. I set the guide pin so that it was just above the maple, but below the height of the plywood.

Routing the outside profile was quick and easy. I did it in four passes, raising the bit each pass. I routed the end grain first and then the side grain to avoid tear out.

Routing the interior profile took a bit more care, but was still quick and easy. I raised the guide pin, started the router, then carefully positioned the workpiece over the bit taking care to ensure the guide pin was inside of the hole cut out in the plywood. Then I plunged the workpiece down on the bit, held the workpiece securely while dropping and locking the guide pin in place. Then it was just a matter of moving the workpiece around within the constraints of the guide pin in the cut out hole. I had to perform these steps a couple of times, turning off the router and raising the bit incrementally each time. When I flipped the piece over it was good to see a perfect reproduction of the circle in the workpiece!

Overall I’m very pleased with the Daisy Pin Router. I think it will work great for the knife display case and I’m sure I will come up with many more uses for it as time goes by.